docs: def set_LObj(self,LObj=None):
          """ Set the LObj attribute, storing objects the instance depends on
  
          For example:
          A Detect object depends on a vessel and some apertures
          That link between should be stored somewhere (for saving/loading).
          LObj does this: it stores the ID (as dict) of all objects depended on.
  
          Parameters
          ----------
          LObj :  None / dict / :class:`~tofu.pathfile.ID` / list of such
              Provide either:
                  - A dict (derived from :meth:`~tofu.pathfile.ID._todict`)
                  - A :class:`~tofu.pathfile.ID` instance
                  - A list of dict or :class:`~tofu.pathfile.ID` instances
  
          """
          self._LObj = {}
          if LObj is not None:
              if type(LObj) is not list:
                  LObj = [LObj]
              for ii in range(0,len(LObj)):
                  if type(LObj[ii]) is ID:
                      LObj[ii] = LObj[ii]._todict()
              ClsU = list(set([oo['Cls'] for oo in LObj]))
              for c in ClsU:
                  self._LObj[c] = [oo for oo in LObj if oo['Cls']==c]